title: Identification of a P2X1 purinoceptor expressed on human platelets.
abstract: It has been proposed that platelets possess a P2X1-purinoceptor-like ligand-gated cation channel, through which Ca2+ enters platelets from the extracellular medium upon ADP or ATP stimulation. In this paper we describe the cloning of human P2X1-specific cDNA from human platelets, K562 and human erythroleukaemic cell lines. Sequence analyses of these cDNAs show 100% nucleotide sequence identity with that of human P2X1 cloned from urinary bladder. Western blotting of platelet lysates separated by SDS-PAGE and probed with anti-P2X1 IgG shows the expected protein with a molecular mass of 60 kDa and a second protein of 45 kDa. These data confirm that platelets possess at least two distinct purinoceptors: a P2T purinoceptor which mediates platelet aggregation, inhibition of adenylate cyclase, and release of intracellular Ca2+ stores and a platelet P2X1 purinoceptor which upon ATP and ADP stimulation mediates the rapid entry of extracellular Ca2+ into platelets.
authors.affiliation: Centre for Veterinary Science, University of Cambridge, United Kingdom.
authors.forename: T J
authors.initials: TJ
authors.lastname: Scase
authors.forename: M F
authors.initials: MF
authors.lastname: Heath
authors.forename: J M
authors.initials: JM
authors.lastname: Allen
authors.forename: S O
authors.initials: SO
authors.lastname: Sage
authors.forename: R J
authors.initials: RJ
authors.lastname: Evans
mesh_terms: D001792:Blood Platelets / Q000737:chemistry*; D015153:Blotting, Western; D015220:Calcium Channels / Q000378:metabolism; D003001:Cloning, Molecular; D004587:Electrophoresis, Agar Gel; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D010957:Plasmids / Q000235:genetics; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058469:Receptors, Purinergic P2X; D011994:Recombinant Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D014162:Transfection / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D015220:Calcium Channels; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D011994:Recombinant Proteins